In an update on an unusual cluster of illnesses and deaths in Liberia in people who attended a funeral, the World Health Organization (WHO) said today that although the outbreak has been classified as a meningococcal disease outbreak, a cofactor may be involved, but so far toxicology tests haven't yielded any new clues.
News of the cluster made headlines in early May, because funeral attendance had played a role in the spread of Ebola in Liberia and other affected West African nations, and some of the symptoms were similar. Within 24 hours, Liberian health ruled out Ebola and suspected meningitis, and tests a short time later at the US Centers for Disease Control and Prevention (CDC) confirmed Neisseria meningitidis serogroup C in some of the patient samples.
During the investigation, authorities had also strongly suspected point-source contamination of food, drink, or water.
Unusual timing complicates outbreak picture
The index patient was an 11-year-old girl who died at the hospital on Apr 23 a day after attending the funeral of a religious leader in Liberia's Sinoe County.
Following the index case and through May 7, 31 cases, 13 of them fatal and 1 involving neurologic complications, were reported from three counties. The main symptoms were abdominal pain, nausea, vomiting, and mental confusion. Some patients had rashes.
All but two of the patients had attended the funeral, and those two were contacts of the index patient.
N meningitidis C was confirmed in 14 of the 31 patients by lab tests or the presence of the hallmark rash. But the unusual timing of the outbreak raises the possibility of a cofactor, the WHO said.
Tests found no toxins
Toxicology testing for pesticide metabolites and toxic metals done on the urine of three patients by the CDC did not find a cause. Extensive testing of food, water, and soft drinks served at the funeral, conducted by Austria's Center for Analytical Chemistry, didn't turn up any contamination after screening for more than 600 fungal and bacterial toxins.
As part of the response, contacts were followed for 21 days. In addition, officials considered meningitis C vaccination but didn't implement it because of the lack of secondary transmission.
Without a clear understanding of the outbreak's epidemiology, the WHO said the risk of recurrence can't be excluded, but it said that, based on what is known about meningococcal disease, the risk is considered low.
Jul 6 WHO outbreak update
May 23 CIDRAP News scan "Meningococcus C strain confirmed in more Liberian cluster patients"